/**
  * Set the values of this builder with the values of the given {@code statistics}.
  *
  * @param statistics the statistics values. If the {@code statistics} is {@code null} nothing is
  *     set.
  * @return this builder.
  */
 public Builder<G, R> statistics(final NumberStatistics<G, R> statistics) {
   if (statistics != null) {
     super.statistics(statistics);
     _fitnessMean = statistics._fitnessMean;
     _fitnessVariance = statistics._fitnessVariance;
     _standardError = statistics._standardError;
   }
   return this;
 }
 @Override
 public Builder<G, R> statistics(final Statistics<G, R> statistics) {
   super.statistics(statistics);
   return this;
 }